Bcl-2 potentiates the maximal calcium uptake capacity of neural cell mitochondria.

Published

Journal Article

Expression of the human protooncogene bcl-2 protects neural cells from death induced by many forms of stress, including conditions that greatly elevate intracellular Ca2+. Considering that Bcl-2 is partially localized to mitochondrial membranes and that excessive mitochondrial Ca2+ uptake can impair electron transport and oxidative phosphorylation, the present study tested the hypothesis that mitochondria from Bcl-2-expressing cells have a higher capacity for energy-dependent Ca2+ uptake and a greater resistance to Ca(2+)-induced respiratory injury than mitochondria from cells that do not express this protein. The overexpression of bcl-2 enhanced the mitochondrial Ca2+ uptake capacity using either digitonin-permeabilized GT1-7 neural cells or isolated GT1-7 mitochondria by 1.7 and 3.9 fold, respectively, when glutamate and malate were used as respiratory substrates. This difference was less apparent when respiration was driven by the oxidation of succinate in the presence of the respiratory complex I inhibitor rotenone. Mitochondria from Bcl-2 expressors were also much more resistant to inhibition of NADH-dependent respiration caused by sequestration of large Ca2+ loads. The enhanced ability of mitochondria within Bcl-2-expressing cells to sequester large quantities of Ca2+ without undergoing profound respiratory impairment provides a plausible mechanism by which Bcl-2 inhibits certain forms of delayed cell death, including neuronal death associated with ischemia and excitotoxicity.

Full Text

Duke Authors

Cited Authors

  • Murphy, AN; Bredesen, DE; Cortopassi, G; Wang, E; Fiskum, G

Published Date

  • September 3, 1996

Published In

Volume / Issue

  • 93 / 18

Start / End Page

  • 9893 - 9898

PubMed ID

  • 8790427

Pubmed Central ID

  • 8790427

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.93.18.9893

Language

  • eng

Conference Location

  • United States